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feat: add solutions to lc problem: No.1712 (doocs#807)
No.1712.Ways to Split Array Into Three Subarrays
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‎solution/1700-1799/1712.Ways to Split Array Into Three Subarrays/README.md

Lines changed: 65 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -62,15 +62,78 @@
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```python
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class Solution:
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def waysToSplit(self, nums: List[int]) -> int:
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mod = 1e9 + 7
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n = len(nums)
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pre = [0] * (n + 1)
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for i in range(1, n + 1):
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pre[i] = pre[i - 1] + nums[i - 1]
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ans = 0
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for i in range(1, n - 1):
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if pre[i] * 3 > pre[n]:
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break
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left, right = i + 1, n - 1
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while left < right:
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mid = (left + right + 1) >> 1
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if pre[mid] - pre[i] <= pre[n] - pre[mid]:
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left = mid
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else:
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right = mid - 1
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mid_right = left
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left, right = i + 1, n - 1
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while left < right:
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mid = (left + right) >> 1
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if pre[mid] - pre[i] >= pre[i]:
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right = mid
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else:
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left = mid + 1
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ans += (mid_right - left + 1) % mod
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return int(ans % mod)
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```
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### **Java**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```java
73-
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class Solution {
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public int waysToSplit(int[] nums) {
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double mod = 1e9 + 7;
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int n = nums.length;
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long[] pre = new long[n + 1];
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for (int i = 1; i < n + 1; i++) {
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pre[i] = pre[i - 1] + nums[i - 1];
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}
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double ans = 0;
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for (int i = 1; i < n - 1; i++) {
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if (pre[i] * 3 > pre[n]) {
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break;
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}
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int left = i + 1, right = n - 1;
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while (left < right) {
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int mid = (left + right + 1) >> 1;
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if (pre[mid] - pre[i] <= pre[n] - pre[mid]) {
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left = mid;
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} else {
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right = mid - 1;
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}
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}
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int midRight = left;
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left = i + 1; right = n - 1;
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while (left < right) {
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int mid = (left + right) >> 1;
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if (pre[mid] - pre[i] >= pre[i]) {
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right = mid;
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} else {
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left = mid + 1;
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}
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}
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ans += (midRight - left + 1) % mod;
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}
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return (int) (ans % mod);
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}
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}
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```
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### **...**

‎solution/1700-1799/1712.Ways to Split Array Into Three Subarrays/README_EN.md

Lines changed: 65 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -71,13 +71,76 @@
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### **Python3**
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```python
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class Solution:
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def waysToSplit(self, nums: List[int]) -> int:
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mod = 1e9 + 7
77+
n = len(nums)
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pre = [0] * (n + 1)
79+
for i in range(1, n + 1):
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pre[i] = pre[i - 1] + nums[i - 1]
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ans = 0
82+
for i in range(1, n - 1):
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if pre[i] * 3 > pre[n]:
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break
85+
left, right = i + 1, n - 1
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while left < right:
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mid = (left + right + 1) >> 1
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if pre[mid] - pre[i] <= pre[n] - pre[mid]:
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left = mid
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else:
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right = mid - 1
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mid_right = left
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left, right = i + 1, n - 1
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while left < right:
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mid = (left + right) >> 1
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if pre[mid] - pre[i] >= pre[i]:
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right = mid
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else:
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left = mid + 1
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ans += (mid_right - left + 1) % mod
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return int(ans % mod)
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```
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### **Java**
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```java
80-
107+
class Solution {
108+
public int waysToSplit(int[] nums) {
109+
double mod = 1e9 + 7;
110+
int n = nums.length;
111+
long[] pre = new long[n + 1];
112+
for (int i = 1; i < n + 1; i++) {
113+
pre[i] = pre[i - 1] + nums[i - 1];
114+
}
115+
double ans = 0;
116+
for (int i = 1; i < n - 1; i++) {
117+
if (pre[i] * 3 > pre[n]) {
118+
break;
119+
}
120+
int left = i + 1, right = n - 1;
121+
while (left < right) {
122+
int mid = (left + right + 1) >> 1;
123+
if (pre[mid] - pre[i] <= pre[n] - pre[mid]) {
124+
left = mid;
125+
} else {
126+
right = mid - 1;
127+
}
128+
}
129+
int midRight = left;
130+
left = i + 1; right = n - 1;
131+
while (left < right) {
132+
int mid = (left + right) >> 1;
133+
if (pre[mid] - pre[i] >= pre[i]) {
134+
right = mid;
135+
} else {
136+
left = mid + 1;
137+
}
138+
}
139+
ans += (midRight - left + 1) % mod;
140+
}
141+
return (int) (ans % mod);
142+
}
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}
81144
```
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83146
### **...**

‎solution/1700-1799/1712.Ways to Split Array Into Three Subarrays/Solution.java

Lines changed: 37 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,37 @@
1+
class Solution {
2+
public int waysToSplit(int[] nums) {
3+
double mod = 1e9 + 7;
4+
int n = nums.length;
5+
long[] pre = new long[n + 1];
6+
for (int i = 1; i < n + 1; i++) {
7+
pre[i] = pre[i - 1] + nums[i - 1];
8+
}
9+
double ans = 0;
10+
for (int i = 1; i < n - 1; i++) {
11+
if (pre[i] * 3 > pre[n]) {
12+
break;
13+
}
14+
int left = i + 1, right = n - 1;
15+
while (left < right) {
16+
int mid = (left + right + 1) >> 1;
17+
if (pre[mid] - pre[i] <= pre[n] - pre[mid]) {
18+
left = mid;
19+
} else {
20+
right = mid - 1;
21+
}
22+
}
23+
int midRight = left;
24+
left = i + 1; right = n - 1;
25+
while (left < right) {
26+
int mid = (left + right) >> 1;
27+
if (pre[mid] - pre[i] >= pre[i]) {
28+
right = mid;
29+
} else {
30+
left = mid + 1;
31+
}
32+
}
33+
ans += (midRight - left + 1) % mod;
34+
}
35+
return (int) (ans % mod);
36+
}
37+
}

‎solution/1700-1799/1712.Ways to Split Array Into Three Subarrays/Solution.py

Lines changed: 28 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,28 @@
1+
class Solution:
2+
def waysToSplit(self, nums: List[int]) -> int:
3+
mod = 1e9 + 7
4+
n = len(nums)
5+
pre = [0] * (n + 1)
6+
for i in range(1, n + 1):
7+
pre[i] = pre[i - 1] + nums[i - 1]
8+
ans = 0
9+
for i in range(1, n - 1):
10+
if pre[i] * 3 > pre[n]:
11+
break
12+
left, right = i + 1, n - 1
13+
while left < right:
14+
mid = (left + right + 1) >> 1
15+
if pre[mid] - pre[i] <= pre[n] - pre[mid]:
16+
left = mid
17+
else:
18+
right = mid - 1
19+
mid_right = left
20+
left, right = i + 1, n - 1
21+
while left < right:
22+
mid = (left + right) >> 1
23+
if pre[mid] - pre[i] >= pre[i]:
24+
right = mid
25+
else:
26+
left = mid + 1
27+
ans += (mid_right - left + 1) % mod
28+
return int(ans % mod)

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